1. Field of the Invention
The invention relates to skin cleaning compositions containing major amounts of acyl isethionates in combination with specific mildness enhancing co-actives such as, for example, specific betaines, amido sulfosuccinates, or combinations of the two.
2. Prior Art
Traditionally, soap has been utilized as a skin cleanser. Soap is, however, a very harsh chemical. Irritated and cracked skin result from use of soap, especially in colder climates. There are, however, certain benefits from the use of soap including low cost, ease of manufacture into bars, and good lathering properties.
There has been much commercial activity in attempting to replace soaps with milder surfactants. The introduction of mild synthetic detergent toilet bars, especially those based on sodium cocoyl isethionates, has been particularly successful. Patents relating to this technology include U.S. Pat. No. 2,894,912 (Geitz) disclosing a detergent bar containing 30-70% C.sub.6 -C.sub.18 acyl esters of isethionic acid, a suds boosting detergent salt such as 10% alkyl sulfate and 2.5-25% soap.
There appears to be no teaching in the art of a solid detergent bar (one embodiment of the invention) having a specific betaine used in combination with acyl isethionates of specified acyl chain lengths (i.e., greater than 30% C.sub.14 or lower in a solid detergent bar) and no recognition that the use of betaine in such compositions provides mildness as well as improved lathering properties relative to similar bars with different acyl chain distributions (i.e., 25% or less C.sub.14 or lower in a solid detergent bar).
In JP 62 141 098, acyl isethionate and carboxy betaine are included in a surfactant base for shampoos and soaps which contain alpha-glucan to impart a smooth feel to skin and hair. There is no mention of acyl chain distribution or of consumer differences (e.g., in lathering) based on such differences.
JP 60 008 398 discusses a similar utility in which dried marmelo fruit seed is used to impart a smooth feel to skin and hair. This reference does not appear to suggest that the isethionate and betaine be used in combination, nor does it suggest that such a combination would have any beneficial effect.
JP 60 161 498 to Shiseido (cited in U.S. Ser. No. 563,468 to Carque et al., filed Aug. 7, 1990) provides an anti-dandruff shampoo with good cleaning and foaming composed of acyl isethionate/lauryl betaine mixtures in a weight ratio of 5:1 to 1:5. There is no teaching of the distribution of the acyl chain length or that the distribution could affect lathering properties of the composition.
JP 62 141 098 to Shiseido (cited in U.S. Ser. No. 563,468 to Carque et al.) teaches shampoo compositions comprising as possible ingredient anionic surfactants such as acyl isethionates and surfactants such as betaine in addition to 0.01-20.0% by weight pullulan. There is no teaching that the two actives should be used together or of the chain distribution of the acyl isethionates. In addition, these compositions are shampoo compositions, not toilet bars.
JP 60 181 200 discusses the use of a propane diol type antibiotics to prevent rancidity and improve perfume stability. Acyl isethionate and betaines are mentioned as possible surfactants for the soap base.
In EP 0,117,135, acyl isethionate and carboxy betaines are included in a surfactant base for shampoos which contain polymers to improve antimicrobial and anti-dandruff efficacy.
JP 7,614,907 discusses the use of betaines in a hard transparent soap formulation. Acyl isethionate may also be included. There is no mention of acyl chain distribution.
JP 63 139 998 discusses a skin detergent blended with clay mineral. Acyl isethionate and betaine are included as possible surfactants. These need not be used together and there is no mention of acyl chain distribution.
U.S. Pat. No. 4,137,191 to Lohr teaches that betaines may be used in combination with anionic surfactants in detergent compositions.
U.S. Pat. No. 3,950,417 to Verdecchi et al. teach betaines may be used with anionic surfactants such as acyl isethionate in detergent compositions.
As indicated above, in none of the above references is it taught to combine acyl isethionate (let alone those having a specific distribution of acyl chain length) and betaines in toilet bar compositions; or is it recognized that this combination may provide both mildness and improved lathering of the bar.
In a second embodiment of the invention, acyl isethionates of defined chain length distribution are used in combination with amido sulfosuccinates.
JP 63 225 700 to Kanebo discloses mild, solid detergent compositions containing acyl isethionate and alkyl sulfosuccinate. The reference does not teach a range of acyl carbon chain lengths from C.sub.6 -C.sub.18 or the use of amido sulfosuccinate. The use of amido sulfosuccinates rather than alkyl sulfosuccinates provides unexpected advantages in mildness enhancement.
U.S. Pat. No. 4,007,128 to Prince teaches use of acyl isethionate and C.sub.12 -C.sub.14 alkanesulfonates. There is no mention of amido sulfosuccinates in the Prince reference.
U.S. Pat. No. 4,749,515 to Miyamoto et al. teaches liquid detergent compositions disclosing use of acylated amido monoesters of sulfosuccinic acid.
U.S. Pat. No. 4,954,282 to Rys et al. is directed to the enhanced mildness observed using stearoyl isethionate relative to cocoyl isethionate. To the extent that the patent shows compositions comprising stearoyl isethionate (and no sulfosuccinate) are significantly milder (relative to a commercially available bar) than compositions comprising cocoyl isethionate (and no sulfosuccinates), a person of ordinary skill in the art would have no expectation whatsoever (and in fact might have the opposite expectation) that addition of sulfosuccinate would enhance the mildness of a composition comprising a cocoyl isethionate to the point where it is significantly milder than a commercially available bar.
U.S. Pat. No. 4,335,025 to Barker discusses synthetic detergent bars containing critical amounts of components. For example, alkali metal salts of C.sub.8-16 alkyl sulfosuccinate together with a selected water soluble anionic detergent which may include a C.sub.10-16 acyl isethionate, a waxy extender such as a C.sub.12-22 fatty acid or alcohol and the like, and other optional extenders. The ratio of surfactant to sulfosuccinate appears to be outside that of this aspect of the invention.
U.S. Pat. No. 3,901,832 to Dugan et al. discusses a detergent bar containing a monoalkyl sulfosuccinate and a specific plasticizer in detergent cakes.
U.S. Pat. No. 3,989,647 to Prince discusses a synthetic toilet bar containing selected amounts of an alkane sulfonate, a fatty acid, and a binder modifier, which may be an alkyl sulfosuccinate.
U.S. Pat. No. 4,812,253 to Small et al. discusses various compositions containing polymeric skin mildness aids, moisturizers, soap and selected surfactants which include acyl isethionates and alkyl sulfosuccinate.
U.S. Pat. No. 4,211,675 to Machin (cited in the European Search Report corresponding to U.S. Serial No. 477,682 to Rys et al., a parent of the subject CIP is directed to detergent bars containing 20-70% acyl (C.sub.8 -C.sub.22) isethionates with 5-30% C.sub.6 -C.sub.22 sucrose esters to increase slip properties of the bar. Optional ingredients which may be added include dialkyl (C.sub.6 -C.sub.9) sulphosuccinates and monoalkyl (C.sub.10 -C.sub.12) ethoxylated sulphosuccinates. There is no disclosure of amido sulphosuccinates or of a specific distribution of acyl chain lengths.
U.S. Pat. No. 3,793,215 to Smith (cited in the European Search Report corresponding to U.S. Ser. No. 477,682 to Rys et al., a parent of the subject CIP) discloses detergent bars with a major amount of anhydrous water-soluble higher fatty acid soap and up to 30% synthetic detergent, as a lime soap dispersing agent, including fatty acid amides of sulphosuccinic acid of defined formula. A marked reduction in lime soap curd formation is demonstrated, but varying the amount of synthetic detergent from 0-30% has no significant effect on mildness. There is no disclosure of a bar comprising the synthetic detergent and acyl isethionate and no reference to improving mildness of compositions.
DE-A-3 335 705 (cited in the European Search Report corresponding to U.S. Ser. No. 477,682 to Rys et al., a parent of the subject CIP) discloses a liquid carpet cleaner containing fatty acid ethanolamide sulphosuccinate and sulphonated fatty acid ester. Compared with known cleaners, the composition is said to have various properties improved. The reference is not concerned with mildness of a skin cleaning toilet bar.
None of the references appear to teach the specific combination of isethionate and amido sulfosuccinate taught by this aspect of the invention.
In a third embodiment of the invention, the compositions of the invention comprise acyl isethionate in combination with betaines and amido sulfosuccinates. Bar compositions comprising this combination of actives have been made and shown to be milder than commercially available mild bars. In a preferred aspect of this embodiment of the invention, the betaine and amido sulphosuccinate actives are used in equal parts.
Applicants are unaware of any reference which teaches this specific combination of ingredients or the mildness advantages observable from this specific combination.
Thus it is an object of the invention to provide a skin cleansing composition based on acyl isethionate as a main active in combination with selected betaines, amido sulfosuccinates or, with a combination of both in order to provide mild compositions with good lathering properties.
It is a further object of the invention to provide other coactives (e.g., nonionic alkylpolyglucosides), which may be used with the betaines, sulfosuccinates or combinations of these two coactives.